Cephalosporin analogues having oxygen in place of sulfur atom in the nucleus have been described in the Journal of Heterocyclic Chemistry, Volume 5, page 779 (1968) by J. C. Sheehan and M. Dadic; German Patent Application (OLS) No. 2,219,601 (1972); the Canadian Journal of Chemistry, Volume 52, page 3996 (1974) by S. Wolfe et al.; the Journal of the American Chemical Society, Volume 96, page 7582 (1974) by B. G. Christensen et al.; Japanese Patent unexamined Publication No. 49-133,594; Japanese Patent unexamined Publication No. 51-149,295 by Beecham Group Ltd.; and Japanese Patent Unexamined Publication No. 52-65,292.
In a previous invention made by two of the present inventors, it was found that the compounds of the following formula had superior characters to the known and described compounds: ##STR5## (wherein Ar' is phenyl, thienyl, hydroxyphenyl, or acyloxyphenyl;
Now, according to this invention, one or more halogens are introduced into the aryl part (Ar') attached to the malonamido groups to achieve some improvements in antibacterial activities and pharmacodynamic properties. These improvements form the bases for this invention.